Method of effecting combustion of fluid fuel



2 sheets-sheet 1 lan. 1, 1935. c. HUFF METHOD OF' EFFECTING COMBUSTION OF' FLUID FUEL Filed. Maron 12. 1930 Jan. 1, 1935. c, HUFF i 1,986,201

METHOD OF EFFECTING COMBUSTION OF' FLUID FUEL Filed March 12v, 1930 2 Sheets-Sheet 2 Patentes-Jan. 1', 1935 [UNITED STATES ME'rnoD oF nrifiic'rnwdA coMUsTIoN ory Lyman C. Hun', Winne'tka, Ill.

lapplication Much 12, 1930, serial No. 435,144

' z claims. (c1. 15a-117.5)

This invention relates l to improvements in a method and means for burning uid fuel in a furnace, and in`one specific embodiment relates tothe burning of fuel oil in domestic furnaces.

Among the diiculties encountered in the burning of oil in domestic furnaces may be mentioned, noise, diiilculty in obtaining complete combustion and the jclogging or coking of the burners, the latter being particularly true when heavy fuel oil is used. v

In many of the burner constructions heretofore devised, in order to suitably atomize the fuel,

the fuel was forced under pressure through a nozzle having a small orifice. Because ofl the restricted area of they orifice the use of heavy oil wasv not always feasible, and in addition, because of the intense heat existen't at the orice, the oil would destructively distill, producing pitches and coke therein and clogging the nozzle. This, of course, necessitated the frequent dismantling and cleaning of the burner'.

Accordingly, one of the salient features of the present invention resides in a means and method of injecting oil fuel into the combustion chamber of a furnace under such conditions that, although a heavy fuel oil is usedthe nozzle will not overy heat and form undesirablecoke or pitch therein nor will the oil clog the nozzle.

Another important feature of the present invention resides in the emc'ient method of admixing the air and fuel to produce perfect combustion of the fuel in the combustion Ichamber. kIn

v addition, the air used for atomizing the fuel may atomize the oil issuing. therefrom and complete-` `ly surrounding said atomized fuel with a nlm of air, 'and subjecting said-mme' to beth radiant and convection heat, thereby eifecting completey lcombustion of the fuel.' The passage of the air in the vicinity' of the' fuel discharge nozzle cools said nozzle and prevents overheating thereof.

vThe instrumentalities involved in my inven'- tion .are susceptible to ready adjustment and regulation; are quickly de mountable and interchangeable; can operated simply and eiliciently; and can be constructed economically and readily marketed. l

Other and further important objects of the invention will be'apparent from 4the accompanying drawings and following detail description.

In the drawings, Fig. 1 is a side elevation, partly in section, showing the arrangement of apparatus suitable for carrying out my invention.'

Fig. 2 is a sectional view. taken on the line. 2-2ofFig.1.

Fig. 3 is a detail sectional'elevation, illustrating the burner proper.

Fig. 4 is a frontelevational view ofthe burnen as shown in Fig. 3.

Referringin detail to thedrawlngs, 1 indic ates 1a furnace having walls 2 of suitable insulating material. The furnace 1 may 'take the form of a hot air furnace, a hot water.'or steam furnace or in general, any typev of heating furnace used for industrial or domestic purposes. Furnace l may be provided with a combustion chamber 3, having walls 4 constructed of refractory material such as rebrick, plastic flrebrick` or the like, or if desired, the walls 4 may be constructed of a heat resisting metal such as chrome nickel steel orv some materialhaving like characteristics. l The cross-sectionalcontour of the combustion chamber 3 may be of any desirable form, but as will hereinafter be more fully brought out, a curvilinear contour may be'preferable. A plurality of piers 5 may beA disposed.

inthe chamber 3, as shownbest inFig. 2. The

chamber walls 4. The piers, if so desired, may

rbe made adjustable so' as to vary the circulatory path of the comb`ustion gases. A cover 6 of the same material may be mounted upon the top of the piers 5 in such a manner as to bridge the, space included therebetween.v An aperture 7 is provided in the wall 4-of the combustion chamber 3 and in the wall 2 of the lfurnace 1. The wall 4 may extend inwardly, as shown best at 3 in Fig. 2, in the vicinity of the aperture 7, the contour of the wall 4 at'this point conforming more or Iless to the contour of the ends of the piers 5. 'I'he upper portion of theI Y combustion chamber wall 4 may be curved inwardly as shown at 9 in Fig. 1 so as to direct the combustion gas circulating in the chamber 3 and prevent the gas from Acontacting the cold .walls 2 ofthe furnace proper.

l-A blower 10 driven by motor 11 may be mounted upon a suitable platformforv support 12 adjacent the furnace 1. The blower 10 may be adapt- 7. A worn gear may be mounted upon the end of theblower shaft 16 and is adapted toturn therewith. The gear 15 may mesh with a worm wheel 17 mounted upon shaft 18 of fuel pump 19. The pump 19 may be of conventional design suitable for the pumping of 'oils of various viscosities from light oils to heavy fuel oils.

Oil may be `drawn from a suitablesource of supply (not shown) through intake pipe 20 and pump 19 and may be discharged through pipe 21 to pipe 22. v'Ihe pipe 22 may be connected into the conduit 13 'through a removable plate 23, the lower portion of said pipe being adapted to discharge adjacent the nozzle 14, which will Aarea. ofthe conduit 13. A lower segment 27 ofl` the nozzle may be hinged at 28 and by means ofthe screw 29 may be locked at various angular positions. A spider 30 is removably positioned at the end of the nozzle 14 and may be provided with a-central downwardly sloping conduit 31 into which the discharge' end of the fuel pipe 22 connects.; Radiating from the conduit 31 as a center is a plurality of fins or extensions 32, the

outer ends of which terminate adjacent the inner surface of the nozzle 14, A baille or air foil 33 may be mounted upon a plurality of the iins 32 and may provide air passageways between the foil andthe bottom of the nozzle and between the foil and the lower side of the conduit 31,

designated as 34 and 35, respectively. Each of the iins 32 may be provided with adjustable dampers 36. 'l

In carrying out my invention the motor 11 may be energized by suitable switching means (not shown) or, if desired, the motor may be thermostatically controlled. Air is forced by the blower 10 through the conduit 13 and issues from the nozzle 14. Simultaneously, fuel is delivered from the pump 19 through pipe 21 and pipe 22 to the conduit 31 and in addition a quantity of air will be drawn into the pipe 22 through the opening at the U bend 24. The sparking means (not shown) may be turned on and the mixture of fuel and air issuing from the conduit 31 and the air issuing from the nozzle 14 per se will be ignited.

As has been hereinbefore described. the conduit 31 is sloped downwardly so that oil issuing from v the pipe 22 will flow by gravity down the inclined lower surface of said conduit. The conduit 31 may be formed egg-shaped in section providing a channel 37 at the lower portion thereof. By this provision the fuel flowing through the conduit is concentrated and channelled at the bottom of the conduit, thus increasing its velocityV of flow. The oil upon flowing through the channel 37 reaches the downwardly extending tip 38 fromdwhich the fuel drips. The drops of fuel as they form on the tip 38 are caught by the stream of air from the passages `34 and are carried upwardly and outwardly into the combustion chamber 3. AIt can be readily observed that the air issuing from the passages 34 and 35, due to the peculiar shape of` the nozzle 14, is focused, as it were, along one line in the combustion chamber, as indicated by the arrows 39 in Fig. 3. It can also be readily seen that the fuel picked up by the air streams issuing from the passageways 34 will be carried by said air to the common point 39 `and from there the united -streams surrounding the suspended fuel pass on into the combustion chamber. The downwardly extending tip 38 causes the air issuing from the passage 35. to eddy thereby tending to agitate the suspended fuel, breaking it up into a ne droplet form. By the provision of the adjustable ylip 27 the angle of the stream issuing from the passageway 34 may be varied'as desired. A

It will be observed that fuel which may drip from the tip 38 will notbe caught by the lip 27 inasmuch as said lip does not extend as far into the combustion chamber as the tip 38. Hence, the drip of fuel from the tip 38 will fall to the bottom of the combustion chamber 3 and may be removecL therefrom through the drain 40. A safety trip ,bucket (not shown) may be positioned beneath the discharge of the drain 40.

As has been hereinbefore mentioned, one of the most troublesome features existent in oil burner nozzles heretofore devised, comprises the overheating of the fuel orifice and the consequent formation of pitch or coke-like material which clog said orifice. This is particularly true when heavyoils are used. To obviate this disadvantageous feature, particular attention has been directed to the cooling of the fuel conduit 31. The provision of the fins 32 tends to remove heat from thel conduit 3l by conduction, the heat being car .ried from the fins by the passage of the air through the various passageways 34 and 35. In addition, the air foil or baille 33 directs a stream of air into intimate contact with the lower portiony of the conduit, further cooling said conduit.'

A further provision for cooling resides in the novel design of the face of the conduit 31, it being readily seenlthat no flat surfacesare exposed to the heat from the combustion chamber 3.

In all oil burner nozzles heretofore devised, overheating of theI fuel orifice and the 'resulting formation of coke or pitch therein, is most apt to occur when the blower is stopped. It is obvious that, at the moment of stopping the blower, a quantity of fuel will remain` in the fuel orifice, and inasmuch as no air is provided for cooling, the radiant heat from the combustion chamber soon heats the orifice toa high temperature thereby intensely heating the oil and forming pitch and carbon in the orifice. To obviate this difficulty suitable switching or relaymeans has sometimes been provided to continue the operation of the blower a shorttime after the fuel is shut off. The objectionable feature of this operation is, that the excess air delivered to the furnace tends to cool the same, thereby reducing its efficiency.

In my invention, the blower may be shut off simultaneously with the shutting off of the fuel, the cooling arrangement being so designed that natural draft passing through the nozzle 14 is suicient to properly cool the conduit 31. 0f course, if desired, the blower may be shut oif after shutting off of the-fuel; in which case a suitable .disconnecting means (not shown) may be provided between the blower shaft 16 and the pump shaft 18.

The dampers 36 which control the ow of air through the various passageways may be adjusted to suit varying conditions of ring, ,fuel and blower pressure.v These adjustments are usually determined and made previous to operation. It

' the readjustment of the dampers 36 can be readily accomplished, or if necessary, the spider 30 may be conveniently repaired or cleaned.

Referringparticularly to Fig. 2, the stream of air and oi1 discharged from the tip of the burner may be projected into the combustion chamber 3 between the piers 5. A jetting action is thereby accomplished inasmuch as a Venturi-like neck 41 is provided between the piers 5 the cover 6 and the I bottom of the combustion chamber 3. By this jetting action, hot gases in the combustion chamber may be induced into the neck 41 and caused to recirculate through it as indicated by arrows 42. Thus, hot gases may be brought into contact with the stream of air and oil, heating them to a high temperature. The recirculated gases further keep the inner surfaces of the neck 41 hot so that these surfaces will radiate more heat through the air stream and to the droplets of oil. The recirculated gases likewise radiate heat directly to the droplets of oil.

It will, therefore, be seen that the droplets of oil which are carried suspended in the center or core of the air stream are heated, and may be caused to vaporize while in suspension and. surrounded by a stream of air. Upon vaporizing, combustion takes place under the most ideal condit-ions, as the oil vapors, when expanding, break through the surrounding stream of air, thus mixn ing thoroughly with it, and affording good coin- 'as it flows through .the tip of the burner.

bustion.

Any unburned vapor has an opportunity to again be brought in contact with a fresh supply of air by the recirculating features afforded in the `lstantially increases the amount 'of .radiant heat given on. 'I'he efficiency of the boiler or furnace will, therefore, be greatly increased,-rst, because large amounts of excess air for combustion are eliminated and second, because more radiant heat is given off from the combustion chamber becauseV ofthe higher temperature maintained therein..

It is apparent that herein is provided a method and means for` effecting substantially perfect combustion of extremely heavy oils. Provision is made for most thoroughly coolingthe oil stream does not come incntact with any hot metal surface as it leaves the burner. It is simply caused to flow on to a stream 'of air which keeps it in suspension and carries it into the combustion chamber where it is quickly heated by radiant heat from the .recirculated gases and chamber walls The oiland vaporizes before contacting directly with any part of the combustion chamber. The radiant heat passes through the stream of air surrounding the oil droplets without substantially losing any heat to the air; Therefore, all the radiant heat is available to heat and vaporize the oil. The incoming air, however, is heated by contacting directly with the hot recirculated gases and is, therefore, heated by convection. In this manner, substantially perfect combustion is effected even with the use of extremely heavy fuel oils.

If desired, the spider 30 may be smoothly ground and then plated with a bright, smooth, metallic substance, such as-for example, chromium or nickel and then highly polished. The bright, smooth, plated surface will reflect the radiant heat laway from the spider and will further prevent the conduit 31 and tip 38 from attaining a temperature suiciently high to distill the oil to pitch or break it down to carbon forming particles.

It cante ready'seen that au'e to the coneshaped formation of the air, as illustrated in Fig.

3 of the drawings, as the same leaves the passages of the nozzle 14, (the apex of the cone being at 39) a zone of reduced pressure exists in the interior of the cone. Hence, the vaporlzation of the fuel ent-rained in the air passing from the conduits 34 is facilitated, furthertending to promote perfect combustion. l

In vorder to facilitate the mixing of air and fuel, the fins 32 may be inclined at an angle to the axis of the' pipe 31, hence imparting a swirling motion to the air discharged from the nozzle 14.

I am aware that many other modicationsmay be made and carried out in connection with my invention without departing from the spirit thereof, hence I do not wish to be limited except as necessitated by the prior art.

I claimr as my invention: y 1. 'I'he method of burning liquid fuel which in,- cludes introducing liquid fuel into a combustion chamber with a supply of air, introducing a sec-l tioned supply of air, introducing said air and fuel 'causing combustion of themixture, diverting a portion of the resulting hot gases of 'combustion the freshly admitted air and fuel is heated.

2. A method of eifectingsubstantially complete 4and recirculating the same into Contact with a freshly admitted supply of fuel and air whereby,

combustion of liquid 'fuel which includes discharg witha supply of air, introducing a second supply of air into said `combustion zone4 a portion of which atomizes said fuel at the point of introduction of the air and fuel into said combustion zone and unitingthe remaining airof said second sup.-

ring liquid fuelinto a combustion zone together ply of air' and the fuel and ai mixture within the.

combustionl vzone lremote from the point of introduction `of the air and fuel into the combustion zone, and subjecting said mixture to radiant heat'. 

